Bacteria <!-- google_ad_client = "ca-pub-0916533245744110"; /* Title links */ google_ad_slot = "9325124257"; google_ad_width = 468; google_ad_height = 15; //-->

Bacteria are a major group of living organisms. They are microscopic and mostly unicellular, with a relatively simple cell structure lacking a cell nucleus, cytoskeleton, and organelles. Bacteria are the most abundant of all organisms. Bacteria can reproduce very quickly and certain types can be very harmful to your pet.